Screening of anti Malassezia furfur active fraction from Rosa chinensis Jacq. and Study on its anti seborrheic dermatitis mechanism

ObjectiveTo screen the plant with optimal inhibitory effects against Malassezia furfur, isolate and identify its most effective antimicrobial active fraction, and investigate its mechanism of action.MethodsThe Oxford cup method and the microbroth dilution method were used to preliminarily screen the best plant extract and polarity fraction from 20 plant species. Silica gel column chromatography was employed for further separation to obtain high-activity fractions. The effects of the high-activity fraction on the growth, biofilm formation, and cell membrane integrity of Malassezia furfur were evaluated using turbidimetry, exogenous sorbitol osmotic protection assay, extracellular alkaline phosphatase activity assay, propidium iodide staining, and crystal violet staining. An inflammatory model in HaCaT cells induced by Malassezia furfur and a SZ95 sebaceous gland cell model were established. The safety of the high-activity fraction was assessed by measuring cell viability using the MTT assay. Nitric oxide release was measured by the Griess assay. The levels of IL-6 and TNF-α in the cell supernatant were detected by enzyme-linked immunosorbent assay. Lipid synthesis rate in SZ95 cells was determined by Nile red staining. Ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) was used to analyze the chemical composition of Fr.2. Combined with protein-protein interaction network, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, its potential targets and pathways against seborrheic dermatitis were predicted.ResultsAmong the extracts from 20 plants, the Rosa chinensis extract showed the best inhibitory effect against Malassezia furfur. Its ethyl acetate fraction exhibited the strongest inhibition. The Fr.2 subfraction displayed the highest activity, with an inhibition zone diameter of (25.30 ± 0.49) mm and a MIC of 1 mg/mL. Fr.2 effectively inhibited the growth of Malassezia furfur (P<0.05) and damaged cell structures such as the cell wall, cell membrane, and biofilm. At safe concentrations (25-100 μg/mL), Fr.2 showed no toxicity to HaCaT and SZ95 human sebaceous gland cells. It dose-dependently reduced the release of inflammatory factors and lipid synthesis in SZ95 cells. UPLC-MS identified 27 compounds in Fr.2, including organic acids, flavonoids (such as myricetin, quercetin, kaempferol), and alkaloids. Its anti-seborrheic dermatitis effects were associated with the modulation of core targets including TNF, CXCL8, PTGS2, STAT3, and EGFR. GO analysis indicated that the common drug-disease targets were mainly involved in neural signaling modulation, inflammatory response regulation, and membrane structure localization; molecular functions were primarily related to protein binding. KEGG pathway analysis further revealed that Fr.2 might exert its therapeutic effects on seborrheic dermatitis by regulating immune-inflammatory pathways, metabolic and vascular-related pathways, and neural signaling pathways.ConclusionRosa chinensis extract can exert antimicrobial effects by damaging the cell wall, cell membrane, and biofilm structures of Malassezia furfur, and possesses certain anti-seborrheic dermatitis activity. This effect may be mediated by both the inhibition of inflammatory signaling pathways and the suppression of lipid synthesis